Which of the following DoS attacks use ICMP? (Choose two)

A SYN attack (or SYN flood) is a DoS attack that exploits the TCP three-way handshake, not ICMP, by sending a flood of SYN requests without completing the handshake.

A Smurf attack leverages ICMP echo requests (pings) directed to a network's broadcast address with a spoofed source IP of the target, causing all hosts on that network to reply to the victim, flooding it with ICMP echo replies.

A Ping of Death attack involves sending an oversized or malformed ICMP packet to a target, which can cause the target system to crash or freeze when it attempts to reassemble the fragmented packet.

A UDP flood is a DoS attack that sends a large number of UDP packets to random ports on a target, aiming to overwhelm the system's ability to process them, and does not specifically use ICMP.

NMAP (Network Mapper) is a network scanner used for discovery and security auditing, not a type of DoS attack itself, although it can be used for reconnaissance prior to an attack.